Linking divergence in phenotypic selection on floral traits to divergence in local pollinator assemblages in a pollination-generalized plant.

Divergent patterns of phenotypic selection on floral traits can arise in response to interactions with functionally distinct pollinators. However, there are a limited number of studies that relate patterns of phenotypic selection on floral traits to variation in local pollinator assemblages in pollination-generalized plant species. We studied phenotypic selection on floral traits of Viscaria vulgaris, a plant that interacts with a broad range of diurnal and nocturnal pollinators, and related divergence in phenotypic selection on floral traits to the expected level of divergence in local pollinator assemblages.

Integration of attractive and defensive phytochemicals is unlikely to constrain chemical diversification in a perennial herb.

Diversification of plant chemical phenotypes is typically associated with spatially and temporally variable plant-insect interactions. Floral scent is often assumed to be the target of pollinator-mediated selection, whereas foliar compounds are considered targets of antagonist-mediated selection. However, floral and vegetative phytochemicals can be biosynthetically linked and may thus evolve as integrated phenotypes.

Pollinator-mediated effects of landscape-scale land use on grassland plant community composition and ecosystem functioning - seven hypotheses.

Environmental change is disrupting mutualisms between organisms worldwide. Reported declines in insect populations and changes in pollinator community compositions in response to land use and other environmental drivers have put the spotlight on the need to conserve pollinators. While this is often motivated by their role in supporting crop yields, the role of pollinators for reproduction and resulting taxonomic and functional assembly in wild plant communities has received less attention.

Evolutionary plant-pollinator responses to anthropogenic land-use change: impacts on ecosystem services.

Agricultural intensification at field and landscape scales, including increased use of agrochemicals and loss of semi-natural habitats, is a major driver of insect declines and other community changes. Efforts to understand and mitigate these effects have traditionally focused on ecological responses. At the same time, adaptations to pesticide use and habitat fragmentation in both insects and flowering plants show the potential for rapid evolution.

Components of local adaptation and divergence in pollination efficacy in a coevolving species interaction.

Selection leading to adaptation to interactions may generate rapid evolutionary feedbacks and drive diversification of species interactions. The challenge is to understand how the many traits of interacting species combine to shape local adaptation in ways directly or indirectly resulting in diversification. We used the well-studied interactions between Lithophragma plants (Saxifragaceae) and Greya moths (Prodoxidae) to evaluate how plants and moths together contributed to local divergence in pollination efficacy.

Differences in mating system and predicted parental conflict affect post-pollination reproductive isolation in a flowering plant.

Mating system shifts from outcrossing to selfing are frequent in plant evolution. Relative to outcrossing, selfing is associated with reduced parental conflict over seed provisioning, which may result in postzygotic, asymmetric, reproductive isolation in crosses between populations of different mating systems. To test the hypothesis that post-pollination reproductive isolation between populations increases with increasing differences in mating system and predicted parental conflict, we performed a crossing experiment involving all combinations of three self-compatible populations (with low outcrossing rates), and three self-incompatible populations (with high outcrossing rates) of the arctic-alpine herb Arabis alpina, assessing fitness-related seed and plant traits of the progeny.

Analysis of trait-performance-fitness relationships reveals pollinator-mediated selection on orchid pollination traits.

Premise: The role of pollinators in evolutionary floral divergence has spurred substantial effort into measuring pollinator-mediated phenotypic selection and its variation in space and time. For such estimates, the fitness consequences of pollination processes must be separated from other factors affecting fitness.

Methods: We built a fitness function linking phenotypic traits of food-deceptive orchids to female reproductive success by including pollinator visitation and pollen deposition as intermediate performance components and used the fitness function to estimate the strength of pollinator-mediated selection through female reproductive success.

Measuring, comparing and interpreting phenotypic selection on floral scent.

Natural selection on floral scent composition is a key element of the hypothesis that pollinators and other floral visitors drive scent evolution. The measure of such selection is complicated by the high-dimensional nature of floral scent data and uncertainty about the cognitive processes involved in scent-mediated communication. We use dimension reduction through reduced-rank regression to jointly estimate a scent composite trait under selection and the strength of selection acting on this trait.

Extensive pollinator sharing does not promote character displacement in two orchid congeners.

Pollinator sharing between close relatives can be costly and can promote pollination niche partitioning and floral divergence. This should be reflected by a higher species divergence in sympatry than in allopatry. We tested this hypothesis in two orchid congeners with overlapping distributions and flowering times.

Genomic Signatures of Sexual Selection on Pollen-Expressed Genes in Arabis alpina.

Fertilization in angiosperms involves the germination of pollen on the stigma, followed by the extrusion of a pollen tube that elongates through the style and delivers two sperm cells to the embryo sac. Sexual selection could occur throughout this process when male gametophytes compete for fertilization. The strength of sexual selection during pollen competition should be affected by the number of genotypes deposited on the stigma.

Evolution of floral scent in relation to self-incompatibility and capacity for autonomous self-pollination in the perennial herb Arabis alpina.

Background And Aims: The transition from outcrossing to selfing is a frequent evolutionary shift in flowering plants and is predicted to result in reduced allocation to pollinator attraction if plants can self-pollinate autonomously. The evolution of selfing is associated with reduced visual floral signalling in many systems, but effects on floral scent have received less attention. We compared multiple populations of the arctic-alpine herb Arabis alpina (Brassicaceae), and asked whether the transition from self-incompatibility to self-compatibility has been associated with reduced visual and chemical floral signalling.

Innate preference hierarchies coupled with adult experience, rather than larval imprinting or transgenerational acclimation, determine host plant use in .

The evolution of host range drives diversification in phytophagous insects, and understanding the female oviposition choices is pivotal for understanding host specialization. One controversial mechanism for female host choice is Hopkins' host selection principle, where females are predicted to increase their preference for the host species they were feeding upon as larvae. A recent hypothesis posits that such larval imprinting is especially adaptive in combination with anticipatory transgenerational acclimation, so that females both allocate and adapt their offspring to their future host.

Incomplete Sterility of Chromosomal Hybrids: Implications for Karyotype Evolution and Homoploid Hybrid Speciation.

Heterozygotes for major chromosomal rearrangements such as fusions and fissions are expected to display a high level of sterility due to problems during meiosis. However, some species, especially plants and animals with holocentric chromosomes, are known to tolerate chromosomal heterozygosity even for multiple rearrangements. Here, we studied male meiotic chromosome behavior in four hybrid generations (F1-F4) between two chromosomal races of the Wood White butterfly differentiated by at least 24 chromosomal fusions/fissions.

Dissecting the Effects of Selection and Mutation on Genetic Diversity in Three Wood White (Leptidea) Butterfly Species.

The relative role of natural selection and genetic drift in evolution is a major topic of debate in evolutionary biology. Most knowledge spring from a small group of organisms and originate from before it was possible to generate genome-wide data on genetic variation. Hence, it is necessary to extend to a larger number of taxonomic groups, descriptive and hypothesis-based research aiming at understanding the proximate and ultimate mechanisms underlying both levels of genetic polymorphism and the efficiency of natural selection.

Lack of gene flow: Narrow and dispersed differentiation islands in a triplet of Leptidea butterfly species.

Genome scans in recently separated species can inform on molecular mechanisms and evolutionary processes driving divergence. Large-scale polymorphism data from multiple species pairs are also key to investigate the repeatability of divergence-whether radiations tend to show parallel responses to similar selection pressures and/or underlying molecular forces. Here, we used whole-genome resequencing data from six wood white (Leptidea sp.

Conflicting selection on floral scent emission in the orchid Gymnadenia conopsea.

Floral scent is a crucial trait for pollinator attraction. Yet only a handful of studies have estimated selection on scent in natural populations and no study has quantified the relative importance of pollinators and other agents of selection. In the fragrant orchid Gymnadenia conopsea, we used electroantennographic data to identify floral scent compounds detected by local pollinators and quantified pollinator-mediated selection on emission rates of 10 target compounds as well as on flowering start, visual display and spur length.

Extreme diversification of floral volatiles within and among species of (Saxifragaceae).

A major challenge in evolutionary biology is to understand how complex traits of multiple functions have diversified and codiversified across interacting lineages and geographic ranges. We evaluate intra- and interspecific variation in floral scent, which is a complex trait of documented importance for mutualistic and antagonistic interactions between plants, pollinators, and herbivores. We performed a large-scale, phylogenetically structured study of an entire plant genus (, Saxifragaceae), of which several species are coevolving with specialized pollinating floral parasites of the moth genus (Prodoxidae).

Versatility of multivalent orientation, inverted meiosis, and rescued fitness in holocentric chromosomal hybrids.

Chromosomal rearrangements (e.g., fusions/fissions) have the potential to drive speciation.

Gene expression profiling across ontogenetic stages in the wood white (Leptidea sinapis) reveals pathways linked to butterfly diapause regulation.

In temperate latitudes, many insects enter diapause (dormancy) during the cold season, a period during which developmental processes come to a standstill. The wood white (Leptidea sinapis) is a butterfly species distributed across western Eurasia that shows photoperiod-induced diapause with variation in critical day-length across populations at different latitudes. We assembled transcriptomes and estimated gene expression levels at different developmental stages in experimentally induced directly developing and diapausing cohorts of a single Swedish population of L.

Diel pattern of floral scent emission matches the relative importance of diurnal and nocturnal pollinators in populations of Gymnadenia conopsea.

Background And Aims: Floral scent is considered an integral component of pollination syndromes, and its composition and timing of emission are thus expected to match the main pollinator type and time of activity. While floral scent differences among plant species with different pollination systems can be striking, studies on intraspecific variation are sparse, which limits our understanding of the role of pollinators in driving scent divergence.

Methods: Here, we used dynamic headspace sampling to quantify floral scent emission and composition during the day and at night in the natural habitat of six Scandinavian populations of the fragrant orchid Gymnadenia conopsea.

Rapid Increase in Genome Size as a Consequence of Transposable Element Hyperactivity in Wood-White (Leptidea) Butterflies.

Characterizing and quantifying genome size variation among organisms and understanding if genome size evolves as a consequence of adaptive or stochastic processes have been long-standing goals in evolutionary biology. Here, we investigate genome size variation and association with transposable elements (TEs) across lepidopteran lineages using a novel genome assembly of the common wood-white (Leptidea sinapis) and population re-sequencing data from both L. sinapis and the closely related L.

Diversification of Trait Combinations in Coevolving Plant and Insect Lineages.

Closely related species often have similar traits and sometimes interact with the same species. A crucial problem in evolutionary ecology is therefore to understand how coevolving species diverge when they interact with a set of closely related species from another lineage rather than with a single species. We evaluated geographic differences in the floral morphology of all woodland star plant species (Lithophragma, Saxifragaceae) that are pollinated by Greya (Prodoxidae) moths.

Nutrient availability affects floral scent much less than other floral and vegetative traits in Lithophragma bolanderi.

Background And Aims: Many plant-pollinator interactions are mediated by floral scents that can vary among species, among populations within species and even among individuals within populations. This variation could be innate and unaffected by the environment, but, because many floral volatiles have amino-acid precursors, scent variation also could be affected by differences in nutrient availability among environments. In plants that have coevolved with specific pollinators, natural selection is likely to favour low phenotypic plasticity in floral scent even under different conditions of nutrient availability if particular scents or scent combinations are important for attracting local pollinators.

Female fecundity variation affects reproducibility of experiments on host plant preference and acceptance in a phytophagous insect.

Reproducibility is a scientific cornerstone. Many recent studies, however, describe a reproducibility crisis and call for assessments of reproducibility across scientific domains. Here, we explore the reproducibility of a classic ecological experiment-that of assessing female host plant preference and acceptance in phytophagous insects, a group in which host specialization is a key driver of diversification.

Floral scent contributes to interaction specificity in coevolving plants and their insect pollinators.

Chemical defenses, repellents, and attractants are important shapers of species interactions. Chemical attractants could contribute to the divergence of coevolving plant-insect interactions, if pollinators are especially responsive to signals from the local plant species. We experimentally investigated patterns of daily floral scent production in three Lithophragma species (Saxifragaceae) that are geographically isolated and tested how scent divergence affects attraction of their major pollinator-the floral parasitic moth Greya politella (Prodoxidae).